Method of flaking wood and rotary tunnel flaker therefor



R- D. KISER Oct. 23, 1962 3,059,676 METHOD OF FLAKING WOOD AND ROTARYTUNNEL FLAKER THEREFOR 2 Sheets-Sheet 1 Filed April 6, 1959 v INVENTORHz iy:

'Richa'rd D. Ifi'ser R. D. KI SER Oct. 23, 1962' METHOD OF FLAKING woonAND ROTARY TUNNEL FLAKER THEREFOR Filed April 6, 1959 2 Sheets-Sheet 2INVENTOR Rickard-D. 'lfz'a'er ATTORNEY 3,059,676 Patented Oct. 23, 1962velopment Co. Inc., Tacoma, Wash, a corporation of Washington Filed Apr.6, 1959, Ser. No. 804,205 6 Claims. (Cl. 144230) This invention relatesto a method of flaking wood and to a rotary tunnel flaker therefor.

In the manufacture of wood flakeboard, wood logs or billets first arereduced to flakes by cutting them across the grain. The flakes then aremixed with a thermosetting resin and size, formed into a felt andconsolidated into the desired thickness and density in a hot press.

In the foregoing sequence, it is important to provide wood flakers whichwill operate rapidly, smoothly, and efliciently so as to produce a largevolume of flakes at minimum cost and at maximum production rate. Inaddition, it'is essential that the flakes produced be of substantiallyuniform thickness, have reasonably sharply defined side edges, and befree from sticks and slivers. Any substantial irregularity in flakedimensions obviously will be reflected in a corresponding irregularityin the properties of the finished board.

This problem is particularly acute in view of the fact that in the usualfiaker the flakes pass as they are formed to gullets located ahead ofthe knife. This requires making a reverse bend around a sharp cornerwhich, in turn, induces breakage of the flakes.

Accordingly it is the general object of the present invention to providea rotary, cross-grain, wood flaker which will produce uniform flakes ata high production rate even when the wood being processed is frangibleand easily broken, as in the case of cedar.

It is another important object of the present invention to provide aflaker of the indicated class which is capable of precision cutting overlong operating periods, but which is easily disassembled and assembledas necessary for servicing and knife sharpening.

In the drawings: I

FIG. 1 is a fragmentary plan view of the herein described flaker;

FIG. 2 is a fragmentary sectional view taken along line 22 of FIG. 1;and

FIGS. 3 and 4 are exploded perspective views of the upper and lowercutter knife assemblies, respectively, in the rotor of FIGS. 1 and 2.

Generally stated, the herein-described method of flaking Wood comprisessevering flakes from a piece of wood with a knife, and guiding theflakes across the leading face of the knife and around the base thereofto a discharge station behind the knife, thereby avoiding reversecurling of the flakes and minimizing breakage thereof.

The apparatus by which the foregoing method is accomplished broadlycomprises a rotor, a knife mounted on the rotor, gib means securing theknife in cutting position, and a passageway through the rotor positionedand dimensioned to pass a flake cut by the knife along the leading faceand around the base thereof to a discharge station behind the same.

Considering the foregoing in greater detail and with particularreference to the drawings:

The flaker of our invention comprises a forged steel, cylindrical rotorprovided with shaft 12. The rotor may be of substantial size, forexample, from 2 to 3 feet long and from 18 to 36 inches in diameter.

A plurality of circumferentially spaced, parallel, longitudinal gibways14, which preferably are wedge-shaped in section, are planed out of therotor. They communicate with knifeways 16 which, in the embodimentillustrated, extend inwardly beyond the gibways and may be formed in thesame operation.

Deep pockets or gullets 18 having a pronounced radius are milled out ofthe rotor periphery at longitudinally spaced intervals along eachknifeway, intercepting the knifeway and gibway.

Wedge-shaped gibs 20, preferably formed in short sections for ease ofhandlingbut shown for simplicity in FIGS. 3 and 4 as extending the fulllength of the rotor, are seated in each of the gibways. The gibs areformed at spaced intervals with transverse, cutaway portions orpassageways 22. These register with gullets 18. Also, the gibs aredrilled and tapped at intervals to receive screws 24 bearing against thebottoms of the gibways in the manner indicated in FIG. 2.

Filling or insert blocks 26 may be provided opposite the gib sectionsreceiving the screws to provide continuity of rotor surface. Cutawayportions in the blocks register with the cutaway portions in the gibs toprovide continuity of passageways 22 inwardly from the rotor surface.

Knives 30 are seated in knifeways 16. Each knife may comprise a flat barsubstantially co-dimensional with the gib. Its outer surface is formedwith projecting knife edge sections 32 alternating with recessed,non-cutting sections 34. The base is cut away at spaced intervalsregistering with the spaced gullets 18 with a radius as indicated at 36to provide a smooth, continuous passageway for flakes from the frontleading side of the knife inwardly along passageway 22 and around theradius 36 to the gullet on the trailing side of the knife.

:In assembling the flaker the gibs and knives are inserted in thegibways and knifeways, respectively, spanning the gullets 18, and thedesired knife adjustment secured. Screws 24 then are tightened down,thus drawing the gibs and insert blocks outwardly and wedging the knivesin position.

Wood is fed to the rotor across a bedplate, not illustrated, andpreferably in a crossgrain direction. The staggered cutting sections ofthe knives thereupon cut flakes which are guided inwardly alongpassageways 22 ahead of the knives and across their front faces, thencearound the passageways forwed in part by cutaway portions 36 at thebases of the knives, and into gullets 18 on the trailing side of theknives. This movement of the flakes is afforded because they are muchthinner than the passageways (FIG. 2). They are stored there pendingcentrifugal discharge from the apparatus upon continued rotation of therotor.

In this manner the flakes are cleanly severed from the woody matrix andpreserved with a minimum of breakage. As a result, a uniform flakeproduct is produced which may be used to great advantage in theproduction of flakeboard of uniform properties.

It is to be understood that the form of our invention herein shown anddescribed is to be taken as a preferred example of the same and thatvarious changes in the shape, size and arrangement of parts may beresorted to without departing from the spirit of our invention or thescope of the subjoined claims.

Having thus described my invention, I claim:

1. The method of flaking wood which comprises severing flakes from apiece of wood with a rotary knife, and guiding the flakes across theleading face of the knife and around the base thereof to a dischargestation behind the knife, thereby avoiding reverse curling of the flakesand minimizing fracturing the same.

2. The method of flaking wood which comprises crosscutting a piece ofwood with a rotary knife having a knife edge and a base, the knife edgebeing maintained substan- 3 tially parallel to the wood grain, therebysevering crosscut flakes from the wood, and guiding the flakes acrossthe leading face of the knife and around the base thereof to a dischargestation behind the knife, thereby avoiding reverse curling of the flakesand minimizing the fracturing thereof in a direction along the grain.

3. A rotary flaker comprising a rotor, a knife having a knife edge and abase mounted on the rotor, and gib means securing the knife in cuttingposition, the rotor being provided with a passageway therethroughpositioned and dimensioned to pass a flake cut by the knife along theleading face and around the base thereof to a discharge station behindthe knife.

4. A rotary flaker comprising a rotor having in its peripheral surface aplurality of spaced, parallel, longitudinal, intercommunicating gibwaysand knifeways, a plurality of gib-knife assemblies seated one in each ofthe gibways and knifeways and each comprising a gib dimensioned to seatin the gibway ahead of the knife and provided with spaced transversepassageways, a knife having projecting cutting sections alternating withrecessed noncutting sections seated in the knifeway with the cuttingsections aligned with and opposite the passageways which accordinglylead across the front face of the knife and around the base thereof,gullet means in the rotor behind the knife communicating with thepassageways in the gib, and means for securing the gib-knife assembly inthe rotor.

5. The flaker of claim 4 wherein a continuous gullet is provided throughthe trailing portion of the gib, around the base of the knife andthrough the rotor behind the knife, thereby providing a way for passageof the flakes along the leading face and around the base of the knife.

6. A rotary flaker comprising a rotor, and a knife mounted on the rotorand having a knife edge and a base, the rotor being provided with aninwardly extending gullet which is traversed by the knife to provide apassageway which extends continuously from the rotor surface inwardalong the leading face of the blade and thence around the base of theblade to the rotor surface on the trailing side of the blade.

References Cited in the file of this patent UNITED STATES PATENTS332,797 Hagerty Dec. 22, 1885 960,526 Erlandsen June 7, 1910 2,477,153Succop July 26, 1949 2,598,933 Nevin June 3, 1952 2,660,242 Lane Nov.24, 1953 2,710,635 Alexander June 14, 1955 2,739,627 Vohringer Mar. 27,1956 2,822,839 Frodermann Feb. 11, 1958 2,836,206 Gaskell May 27, 1958FOREIGN PATENTS 1,033,888 Germany July 10, 1958 179,088 Australia July10, 1954 181,596 Switzerland Apr. 16, 1936 269,389 Germany Jan. 20, 1914802,953 Germany Feb. 26, 1951 1,042,167 France June 3, 1953

